Tracking changes of lymphocyte subsets and pre-inflammatory mediators in full-term neonates with suspected or documented infection

Biomarkers of Neonatal Sepsis: Where We Are and Where We Are Going

Neonatal sepsis is a bacterial bloodstream infection leading to severe clinical manifestations frequently associated with death or irreversible long-term deficits. Antibiotics are the drug of choice to treat sepsis, regardless of age. In neonates, the lack of reliable criteria for a definite diagnosis and the supposition that an early antibiotic administration could reduce sepsis development in children at risk have led to a relevant antibiotic overuse for both prevention and therapy. The availability of biomarkers of neonatal sepsis that could alert the physician to an early diagnosis of neonatal sepsis could improve the short and long-term outcomes of true sepsis cases and reduce the indiscriminate and deleterious use of preventive antibiotics. The main aim of this narrative review is to summarize the main results in this regard and to detail the accuracy of currently used biomarkers for the early diagnosis of neonatal sepsis. Literature analysis showed that, despite intense research, the diagnosis of neonatal sepsis and the conduct of antibiotic therapy cannot be at present decided on the basis of a single biomarker. Given the importance of the problem and the need to reduce the abuse of antibiotics, further studies are urgently required. However, instead of looking for new biomarkers, it seems easier and more productive to test combinations of two or more of the presently available biomarkers. Moreover, studies based on omics technologies should be strongly boosted. However, while waiting for new information, the use of the clinical scores prepared by some scientific institutions could be suggested. Based on maternal risk factors and infant clinical indicators, sepsis risk can be calculated, and a significant reduction in antibiotic consumption can be obtained.

Fighting Antimicrobial Resistance in Neonatal Intensive Care Units: Rational Use of Antibiotics in Neonatal Sepsis

Antibiotics are the most frequently prescribed drugs in neonatal intensive care units (NICUs) due to the severity of complications accompanying neonatal sepsis. However, antimicrobial drugs are often used inappropriately due to the difficulties in diagnosing sepsis in the neonatal population. The reckless use of antibiotics leads to the development of resistant strains, rendering multidrug-resistant pathogens a serious problem in NICUs and a global threat to public health. The aim of this narrative review is to provide a brief overview of neonatal sepsis and an update on the data regarding indications for antimicrobial therapy initiation, current guidance in the empirical antimicrobial selection and duration of therapy, and indications for early discontinuation.

The emerging roles and therapeutic potential of B cells in sepsis

Sepsis is a life-threatening syndrome caused by anomalous host response to infection. The pathogenesis of sepsis is complex, and immune dysfunction is the central link in its occurrence and development. The sepsis immune response is not a local and transient process but a complex and continuous process involving all major cell types of innate and adaptive immunity. B cells are traditionally studied for their ability to produce antibodies in the context of mediating humoral immunity. However, over the past few years, B cells have been increasingly recognized as key modulators of adaptive and innate immunity, and they can participate in immune responses by presenting antigens, producing cytokines, and modulating other immune cells. Recently, increasing evidence links B-cell dysfunction to mechanisms of immune derangement in sepsis, which has drawn attention to the powerful properties of this unique immune cell type in sepsis. Here, we reviewed the dynamic alterations of B cells and their novel roles in animal models and patients with sepsis, and provided new perspectives for therapeutic strategies targeting B cells in sepsis.

C-reactive protein in infants with no evidence of early-onset sepsis

OBJECTIVE

C-reactive protein (CRP) is one of the most extensively used biomarkers in the investigation of early-onset sepsis (EOS). Current evidence suggests the normal kinetics of serum CRP should be considered when evaluating infants for presumable EOS. The current study aimed to evaluate the CRP kinetics, and to establish percentiles in a cohort of term and near-term infants with no evidence of confirmed or clinical EOS.

METHODS

We retrospectively reviewed the medical records of all neonates ≥34 weeks' gestation screened for presumable EOS, from January until December 2019. We also recorded the clinical management, the blood culture, serial CRP, and white blood cell count analysis of each infant. All infants that received antibiotics for confirmed or presumed EOS were excluded from the analysis.

RESULTS

During the study period, 145 infants were detected; 109 (75%) term and 36 (25%) preterm. Term infants had significantly higher median values of CRP at all time points in comparison to preterm infants. Term infants presented a significant rise of CRP at 24 and 36 h, with a peak at 24 h (median 4 (range 1-12) mg/L). Preterm infants had a significant rise of CRP at 24 but not at 36 h, with a peak at 24 h (median 3 (range 1-9) mg/L). In term infants, the 90th percentile of CRP at 24 h was 10.80 mg/L and the 97th percentile was 12.00 mg/L. In preterm infants, the 90th percentile of CRP at 24 h was 7.60 mg/L and the 97th percentile was 8.00 mg/L.

CONCLUSIONS

Term and near-term asymptomatic infants had a rise in CRP during the first days of life. Term infants had a more pronounced CRP response in comparison to preterm infants.

Accuracy of C-Reactive Protein Test for Neonatal Septicemia: A Diagnostic Meta-Analysis

BACKGROUND The aim of this study was to evaluate the diagnostic value of C-reactive protein (CRP) test in detecting neonatal septicemia. MATERIAL AND METHODS We searched the Cochrane Library, PubMed, Springer, MBASE, Elsevier Science Direct, and Medline databases up to March 2017. To collect relevant data on CRP testing in patients with neonatal septicemia, we performed a meta-analysis of positive likelihood ratio (LR), sensitivity, negative LR, specificity and diagnostic odds ratio (dOR) of CRP testing, using Stata 12.0 and Meta-DiSc 1.4 data analysis software. RESULTS Ten studies including 1819 participants were considered in this study. We found that positive LR, sensitivity, negative LR, specificity, and dOR of the CRP test for neonatal septicemia were 5.63 (95% CI=2.86 to 11.09), 0.70 (95% CI=0.66 to 0.75), 0.36 (95% CI=0.21 to 0.60), 0.89 (95% CI=0.87 to 0.91), and 17.99 (95% CI=6.50 to 49.83), respectively. The AUC and Q* index of this meta-analysis were 0.90 and 0.83, respectively. CONCLUSIONS The area under the curve (AUC), negative LR, positive LR, Q* index, specificity, and dOR of the CRP test suggest that it is appropriate for detecting neonatal septicemia.

A meta-analysis of interleukin-6 as a valid and accurate index in diagnosing early neonatal sepsis

We aimed to systematically assess the overall value of interleukin 6 (IL-6) in diagnosing neonates with sepsis. A systematic literature search was conducted using the following electronic databases: PubMed, Embase, and Cochrane, to identify eligible studies through the index words updated till November 2018. Cross-sectional studies, as well as prospective cohort studies, were included in the above-mentioned group of eligible studies. We also searched the literature sources that had a link to the present study, which were further assessed by heterogeneity through the use of a proper-effects model to calculate pooled weighted specificity, sensitivity, and diagnostic odds ratio (DOR). We also conducted summary receiver operating characteristic (SROC) analyses for neonatal sepsis. In the present meta-analysis, there were 31 studies exploring IL-6 for the diagnostic accuracy of neonatal sepsis. The global specificity and sensitivity of IL-6 for neonatal sepsis were as follows: 88% (95% confidence interval [CI]: 83%-92%) and 82% (95% CI: 77%-86%), respectively. The global positive and negative likelihood ratio of IL-6 in diagnosing neonatal sepsis were 7.03 (95% CI: 4.81-10.26) and 0.20 (95% CI: 0.15-0.26), respectively. The global DOR was 29.54 (95%CI: 18.56-47.04) of IL-6. In addition, the area under the SROC was high for IL-6 (AUC = 0.92; 95% CI: 0.89-0.94). In this study, we performed a systematic review and meta-analysis to assess the diagnostic accuracy studies of IL-6 in diagnosing neonatal sepsis. Our results suggested that IL-6 is a valid and accurate index in diagnosing early neonatal sepsis, but it still needs to be combined with other laboratory tests and specific clinical manifestations.

Bifidobacterium bifidum OLB6378 Simultaneously Enhances Systemic and Mucosal Humoral Immunity in Low Birth Weight Infants: A Non-Randomized Study

Probiotic supplementation has been part of the discussion on methods to enhance humoral immunity. Administration of Bifidobacterium bifidum OLB6378 (OLB6378) reduced the incidence of late-onset sepsis in infants. In this non-randomized study, we aimed to determine the effect of administration of live OLB6378 on infants' humoral immunity. Secondly, we tried to elucidate whether similar effects would be observed with administration of non-live OLB6378. Low birth weight (LBW) infants weighing 1500-2500 g were divided into three groups: Group N (no intervention), Group L (administered live OLB6378 concentrate), and Group H (administered non-live OLB6378 concentrate). The interventions were started within 48 h after birth and continued until six months of age. Serum immunoglobulin G (IgG) levels (IgG at one month/IgG at birth) were significantly higher in Group L than in Group N (p < 0.01). Group H exhibited significantly higher serum IgG levels (p < 0.01) at one month of age and significantly higher intestinal secretory immunoglobulin A (SIgA) levels (p < 0.05) at one and two months of age than Group N. No difference was observed in the mortality or morbidity between groups. Thus, OLB6378 administration in LBW infants enhanced humoral immunity, and non-live OLB6378, which is more useful as a food ingredient, showed a more marked effect than the viable bacteria.

Utility of cytokine, adhesion molecule and acute phase proteins in early diagnosis of neonatal sepsis

Background and Aim:

Neonatal infection, including bacterial sepsis, is a major health care issue with an annual global mortality in excess of one million lives. Therefore, this study aimed to evaluate the potential diagnostic value of C-reactive protein (CRP), E-selectin, procalcitonin (PCT), interleukins-6 (IL-6), and tumor necrosis factor-α (TNF-α) both independently and in combination for the diagnosis of neonatal sepsis in its earliest stages.

Materials and Methods:

A total of 320 subjects were included in this study. A prospective cross-sectional study was conducted among neonates admitted to Neonatal Intensive Care Unit at King Abdulaziz Medical City, Riyadh, KSA during January 2013 to August 2015, the study based on three study groups categorized according to clinical symptoms and blood culture result. Study groups include healthy control neonates (n = 80), clinical sepsis (CS) group (n = 80) with clinical signs of sepsis but their blood culture was negative, and sepsis group with clinical signs of sepsis and their blood culture was positive.

Results:

The study observed significant difference in plasma levels of CRP, IL-6, TNF-α, E-selectin, and PCT in patients group when compared with control group (P < 0.001). Furthermore, the levels are significantly different between patient groups including CS and neonatal sepsis group. Moreover, result observed significant difference in CRP and IL-6 in early onset sepsis (EOS) when compared with late onset sepsis (LOS) neonates (P < 0.001 and 0.01), respectively, while there were no significant difference in TNF-α, E-selectin, and PCT between EOS and LOS (P = 0.44, 0.27 and 0.24), respectively. Regarding biomarkers accuracy, the result showed that CRP has the best diagnostic accuracy with cutoff value of 3.6 ng/ml (sensitivity 78% and specificity of 70%). The best combination is shown with CRP and IL-6 in which sensitivity increased to 89% and specificity to 79%.

Conclusion:

It was concluded that infected new-born babies have a higher E-selectin, PCT, IL-6, TNF-α, and CRP compared with the neonates with CS and control. IL-6, TNF-α, and CRP should be measured in combination for mare diagnostic accuracy in neonatal sepsis. Likewise, PCT should be investigated as a part of sepsis screening for all suspected neonates.

Diagnostic value of C-reactive protein in neonatal sepsis: A meta-analysis

The aim of this study was to determine the value of C-reactive protein (CRP) in the diagnosis of patients with neonatal sepsis by a meta-analysis. Potential relevant studies were searched through the PubMed, Embase, and Cochrane Library databases before February 2016. We combined estimates of sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) with their 95% confidence intervals (CIs) of CRP for neonatal sepsis diagnosis. Summary receiver operating characteristic (SROC) curve was applied to evaluate the diagnostic value of CRP. The meta-regression and subgroup analysis were performed when heterogeneity was significant. In total, 31 studies were included in our meta-analysis with 5698 participants. The overall estimates for CRP in the diagnosis of neonatal sepsis were: sensitivity 0.69 (95% CI, 0.66–0.71), specificity 0.77 (95% CI, 0.76–0.78), PLR 3.83 (95% CI, 3.03–4.84), NLR 0.38 (95% CI, 0.31–0.45), and DOR 12.65 (95% CI, 8.91–17.94). The area under the curve (AUC) and Q* index were 0.8458 and 0.7773. Meta-regression analysis showed that heterogeneity was irrelevant to test time, cutoff value, assay method of CRP, neonates, and sepsis type. Heterogeneity still existed but decreased after subgroup analysis. CRP might be a valuable approach for the diagnosis of neonatal sepsis.

TLR-mediated albuminuria needs TNFα-mediated cooperativity between TLRs present in hematopoietic tissues and CD80 present on non-hematopoietic tissues in mice

Transient albuminuria induced by pathogen-associated molecular patterns (PAMPs) in mice through engagement of Toll-like receptors (TLRs) is widely studied as a partial model for some forms of human nephrotic syndrome (NS). In addition to TLRs, CD80 has been shown to be essential for PAMP-mediated albuminuria. However, the mechanistic relationships between TLRs, CD80 and albuminuria remain unclear. Here, we show that albuminuria and CD80-uria induced in mice by many TLR ligands are dependent on the expression of TLRs and their downstream signalling intermediate MyD88 exclusively in hematopoietic cells and, conversely, on CD80 expression exclusively in non-hematopoietic cells. TNFα is crucial for TLR-mediated albuminuria and CD80-uria, and induces CD80 expression in cultured renal podocytes. IL-10 from hematopoietic cells ameliorates TNFα production, albuminuria and CD80-uria but does not prevent TNFα-mediated induction of podocyte CD80 expression. Chitohexaose, a small molecule originally of parasite origin, mediates TLR4-dependent anti-inflammatory responses, and blocks TLR-mediated albuminuria and CD80-uria through IL-10. Thus, TNFα is a prominent mediator of renal CD80 induction and resultant albuminuria in this model, and small molecules modulating TLR-mediated inflammatory activation might have contributory or adjunct therapeutic potential in some contexts of NS development.

Summary: Systemic TNFα mediates myeloid cell and podocyte cross-talk to cause LPS-induced mouse microalbuminuria, a partial model of human nephrotic syndrome, pointing to potential adjunct therapeutic approaches.

Increased monocytes and bands following a red blood cell transfusion

OBJECTIVE

The objective of this study is to analyze the white blood cell changes that occur after a transfusion of red blood cells in order to identify a subclinical inflammatory response in neonates.

STUDY DESIGN

Retrospective analysis of infants who received a red blood cell transfusion in an intensive care nursery. White blood cell results within 24 h pre- to 48 h post-transfusion were collected and analyzed. Statistical analysis included ANOVA, T-test, Mann-Whitney U test, Pearson's correlation and multivariable linear regression.

RESULT

Monocytes (P=0.02) and bands (P=0.035) were increased post-transfusion. There were no differences in monocytes (P=0.46) or bands (P=0.56) between groups who did or did not have blood cultures obtained. There was no difference in monocytes between groups who did or did not have sepsis (P=0.88).

CONCLUSION

We identified an elevation in monocytes and bands in the 48 h following a transfusion in premature infants. Our findings support a possible pro-inflammatory response related to transfusion of red blood cells.

Tumor necrosis factor-α as a diagnostic marker for neonatal sepsis: a meta-analysis

Neonatal sepsis (NS) is an important cause of mortality in newborns and life-threatening disorder in infants. The meta-analysis was performed to investigate the diagnosis value of tumor necrosis factor-α (TNF-α) test in NS. Our collectible studies were searched from PUBMED, EMBASE, and the Cochrane Library between March 1994 and August 2013. Accordingly, 347 studies were collected totally, in which 15 articles and 23 trials were selected to study the NS in our meta-analysis. The TNF-α test showed moderate accuracy of the diagnosis of NS both in early-onset neonatal sepsis (sensitivity = 0.66, specificity = 0.76, Q∗ = 0.74) and in late-onset neonatal sepsis (sensitivity = 0.68, specificity = 0.89, Q∗ = 0.87). We also found the northern hemisphere group in the test has higher sensitivity (0.84) and specificity (0.83). A diagnostic OR analysis found that the study population may be the major reason for the heterogeneity. Accordingly, we suggest that TNF-α is also a valuable marker in the diagnosis of NS.

Flow cytometry in the detection of neonatal sepsis

Neonatal sepsis remains a burden problem by showing minimal initial symptoms of subtle character, nonspecific manifestation, and diagnostic pitfalls. The clinical course can be fulminant and fatal if treatment is not commenced promptly. It is therefore crucial to establish early diagnosis and initiate adequate therapy. Besides clinical symptoms, the most reliable laboratory markers in establishing diagnosis is currently the combined measurement of CRP and a cytokine (IL-6 and IL-8). Due to their different kinetics, a diagnostic gap might occur and thus withholding antimicrobial therapy in clinical suspicion of infection is not acceptable. We therefore need parameters which unerringly differentiate between infants in need for antimicrobial therapy and those who are not. Flow cytometry promises to be a useful tool in this field, allowing the determination of different cellular, dissolved, and functional pathophysiological components of sepsis. Despite technical and methodical advances in flow cytometry, its use in clinical routine is still limited. Advantages and disadvantages of promising new parameters in diagnosis of sepsis performed by flow cytometry, particularly CD64, HLA-DR, and apoptosis, are reviewed here. The necessity of tests to be used as an “ideal” parameter is presented.

Cytokine profiles of preterm neonates with fungal and bacterial sepsis

BACKGROUND

Information on cytokine profiles in fungal sepsis (FS), an important cause of mortality in extremely low birthweight (ELBW) infants, is lacking. We hypothesized that cytokine profiles in the first 21 d of life in ELBW infants with FS differ from those with bacterial sepsis (BS) or no sepsis (NS).

METHODS

In a secondary analysis of the National Institute of Child Health and Human Development Cytokine study, three groups were defined-FS (≥1 episode of FS), BS (≥1 episode of BS without FS), and NS. Association between 11 cytokines assayed in dried blood spots obtained on days 0-1, 3 ± 1, 7 ± 2, 14 ± 3, and 21 ± 3 and sepsis group was explored.

RESULTS

Of 1,066 infants, 89 had FS and 368 had BS. As compared with BS, FS was more likely to be associated with lower birthweight, vaginal delivery, patent ductus arteriosus, postnatal steroids, multiple central lines, longer respiratory support and hospital stay, and higher mortality (P < 0.05). Analyses controlling for covariates showed significant group differences over time for interferon-γ (IFN-γ), interleukin (IL)-10, IL-18, transforming growth factor-β (TGF-β), and tumor necrosis factor-α (TNF-α) (P < 0.05).

CONCLUSION

Significant differences in profiles for IFN-γ, IL-10, IL-18, TGF-β, and TNF-α in FS, BS, or NS in this hypothesis-generating secondary study require validation in rigorously designed prospective studies and may have implications for diagnosis and treatment.

Emerging biomarkers for the diagnosis of severe neonatal infections applicable to low resource settings

More than 500 000 children die each year in low resource settings due to serious neonatal infections. Better diagnostics that can be utilized in these settings to identify infected infants have the potential to significantly reduce neonatal deaths and the associated morbidity. A systematic review was performed and identified more than 250 potential new biomarkers for the diagnosis of serious neonatal infections. Eight of these biomarkers were both high-performance and high-abundance (antithrombin, inter-α inhibitor proteins, interferon-γ inducible protein-10, interleukin-1 receptor antagonist, LPS binding protein, mannose binding lectin, serum amyloid A, resistin, visfatin), and are promising for the diagnosis of serious neonatal infections in low resource settings. Future clinical trials comparing these biomarkers with more traditional biomarkers seem warranted.